Methods have been developed for preparing L-canavanine, L-canaline, O-ureidohomoserine, and L-canavaninosuccinic acid. These compounds, collectively designated the canaline-urea cycle amino acids, are naturally-occurring structural analogues of the ornithine-urea cycle intermediates and posses potent antimetabolic properties. Fundamental studies of the biological effects and mode of action of these amino acid analogues being conducted with the aquatic plant, Lemna minor, and the tobacco hornowrm, Manduca sexta. These studies are designed to provide fundamental information on the autimetabolic properties of amino acid analogues and to encourage their employment as a research tool.